Grooved base for an electric light bulb



FIG. 1 is a perspective view of a grooved base for an electric light bulb with the broken line showing for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a side elevational plan view of FIG. 1;

FIG. 3 is a top plan view of FIG. 1; and,

FIG. 4 is a bottom plan view of FIG. 1. 

The ornamental design for a grooved base for an electric light bulb, as shown and described. 